The invention relates to a shot-blasting installation for blasting work pieces made from light metal alloys, comprising at least one blasting chamber for receiving the work pieces that are to be blasted, at least two blasting wheels arranged in walls of the blasting chamber for introducing a blasting agent into the blasting chamber, and a separator for separating the mixture of blasting agent and material that has been removed by blasting.
To enable as much weight as possible to be saved, cast work pieces made from light metal alloys, in particular made from aluminium and magnesium alloys, are increasingly being used in motor vehicle construction. The work pieces, which are produced by die-casting or sand-casting processes, have to be deburred and cleaned after casting. After the casting operation, the work pieces often have an uneven and irregular outer surface. To improve the appearance of the work pieces, the outer surfaces have to be ground, polished and/or blasted. Blasting with particulate blasting agents can also be used to alter the physical structure at the surface of the cast work piece. By way of example, it is possible to compact or harden the cast workpiece at the surface and make it more resistant to abrasion or to improve its sliding properties.
U.S. Pat. No. 5,014,469 has disclosed a blasting installation comprising a blasting chamber with two blasting wheels, an expansion chamber, a conveyor installation and a separator. The work pieces which are blasted in the blasting chamber are plates or metal sheets which are passed through the blasting chamber over a roller conveyor. The mixture of blasting agent and material removed by blasting is blown off the surface of the work piece and passed via a metal diverter sheet into a space with a conveyor installation. As it drops off the metal diverter sheet, the mixture is first of all separated into a stream comprising coarser, heavier material and a stream comprising finer, lighter material. The heavier material is fed via the conveyor installation to an additional separator. In the separator, which is arranged above the blasting chamber, the second actual separating-off of the blasting agent is carried out. The lighter material is sucked out or separated off by a blower via an expansion chamber in a separating cyclone and a dust collector.
Working on the basis of this prior art, it is an object of the invention to provide a shot-blasting installation which has the simplest possible construction and ensures operation is as reliable and safe as possible in particular for work pieces made from magnesium alloys.